Novel Diastereoselective Synthesis of Bicyclic -Lactams through Radical Cyclization and Their Reduction toward 2-(1-A

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• 作者：Erika Leemans ; Matthias D'hooghe ; Yves Dejaegher ; Karl W. T&ouml ; rnroos ; Norbert De Kimpe
• 刊名：Journal of Organic Chemistry
• 出版年：2008
• 出版时间：February 15, 2008
• 年：2008
• 卷：73
• 期：4
• 页码：1422 - 1428
• 全文大小：144K
• 年卷期：v.73,no.4(February 15, 2008)
• ISSN：1520-6904

文摘

BLE>FIGR ID=jo702263pn00002>bscribe/journals/joceah/73/i04/figures/jo702263pn00002.gif" ALIGN="left" HSPACE=5>1-Allyl- and 1-(3-phenylallyl)-substituted 4-(2-bromo-1,1-dimethylethyl)azetidin-2-ones were transformedinto 3-substituted 7-alkoxy-5,5-dimethyl-1-azabicyclo[4.2.0]octane-8-ones through radical cyclization bymeans of n-tributyltin hydride and AIBN in toluene with excellent diastereocontrol (f">99%). The radicalcyclization of 4-(2-bromo-1,1-dimethylethyl)-1-(2-methylallyl)azetidin-2-ones afforded 8-alkoxy-3,6,6-trimethyl-1-azabicyclo[5.2.0]nonan-9-ones in good diastereomeric excess (75-78%). The reductive ringopening of 1-azabicyclo[4.2.0]octane-8-ones and 1-azabicyclo[5.2.0]nonan-9-ones with lithium aluminumhydride resulted in novel 2-(1-alkoxy-2-hydroxyethyl)piperidines and -azepanes, which were isolated assingle isomers.